The amount of money borrowed for PFI deals increased 67% to £8.2bn last year, according to research by Thomson Financial.
Rod Morrison, head of project finance at Thomson, said the reason for the sharp rise was that deals were going through more quickly. He said that the London Underground Metronet deal and the Ministry of Defence's communication satellites Skynet project accounted for £3.2bn of the debt.

He said: "The figures show that more deals are closing as it is a settled market now. It is easier to close deals than it was five or six years ago."

In 1997, PFI debt in the UK stood at £1bn.

Morrison added that borrowing this year might be slightly down on last, but would still be significantly higher than at any other time since PFI was introduced.

Noteworthy projects include a £600m deal with the Ministry of Defence at Colchester garrison in Essex and a £1bn contract for the Allenby and Connaught barracks refurbishment in the South-east.

The amount borrowed was highest in the transport sector, which accounted for nearly £3.8bn.

The bank that raised the most money for PFI deals last year was the Royal Bank of Scotland (see graph).

It organised finance on 12 contracts worth nearly £1.5bn. They included a £177m Docklands Light Railway extension in south-east London and a £333m Metronet bond.